Coordinate system input devices are now coming into wide use where each coordinate input device comprises a coordinate system detection means called "touch sensor" of optical type or capacity measuring type disposed on a front surface of a video display such as CRT display or LCD, so that when a finger or other solid directly touches a video display screen exhibiting images, a coordinate system input operation against a host computer is effected.
Such coordinate system input devices disposed and used on a front surface of a display apparatus for a signal input operation are disclosed by U.S.A. Pat. Nos. 4,563,578; 4,558,313; 4,555,157; 4,553,842; 4,553,254; 4,542,375; 4,521,870; 4,520,357; 4,517,559; 4,511,760; 4,507,557; 4,476,463; 4,459,476; 4,423,299; 4,313,109; 4,055,726; 3,916,099 and others which uses various detection means.
In these prior art devices, it is required that a specific position of a cursor on the screen of the video display, according to image coordinate system data from a host computer accurately coincide with detected coordinate system data obtained from the coordinate system detection means upon a finger touch on the cursor. If the image coordinate system data of the cursor does not coincide with the detected coordinate system data, the host computer erroneously judges that a position other than that of the cursor was instructed by a user's finger, even when a user just touches the position of the cursor on the video display.
In this connection, the prior art technology involves a problem that the coordinate system detection means has to be disposed in accurate coincidence with the coordinate system axes of the video display in order to maintain coincidence between the image coordinate system data of an image indicated on the video display and the detected coordinate system data obtained from the coordinate system detection means.
It is therefore a first object of the invention to provide a coordinate system input device configured to correct the detected coordinate system data from the coordinate system detection means into a value corresponding to the image coordinate system data of an image indicated on the video display and to thereafter output the corrected value.
In the prior art device, the cursor moves following to a movement of a finger put on the cursor indicated on the video display. More specifically, the cursor is indicated on the video display in accordance with a detected coordinate system data of the finger obtained from the coordinate system detection means upon a coordinate system input operation.
However, the finger put on the cursor during a coordinate system input operation hides the cursor and makes it difficult for a user to readily recognize the position of the cursor. Additionally, in a large-scaled video display screen on which the cursor must move over a large distance, a large movement of a finger or other touching element is required, and this decreases the operability of the device.
It is therefore a second object of the invention to provide a coordinate system input device configured to move the cursor on the video display in a mouse mode by coordinate system input operation against the screen other than the cursor.
A third object of the invention is to provide a coordinate system input device configured to move the cursor on the video display in a mouse mode by a coordinate system input operation against the screen other than the cursor and to commence a procedure according to the cursor coordinate system data upon completion of coordinate system input operation.